pinctrl: mediatek: paris: Rework mtk_pinconf_{get,set} switch/case logic

pinctrl: mediatek: paris: Rework mtk_pinconf_{get,set} switch/case logic

The current code deals with optional features by testing for the
function pointers and returning -ENOTSUPP if it is not valid. This is
done for multiple pin config settings and results in the code that
handles the supporting cases to get indented by one level. This is
aggrevated by the fact that some features require another level of
conditionals.

Instead of assigning the same error code in all unsupported optional
feature cases, simply have that error code as the default, and break
out of the switch/case block whenever a feature is unsupported, or an
error is returned. This reduces indentation by one level for the useful
code.

Also replace the goto statements with break statements. The result is
the same, as the gotos simply exit the switch/case block, which can
also be achieved with a break statement. With the latter the intent
is clear and easier to understand.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220308100956.2750295-8-wenst@chromium.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>